1. Field of the Invention
The present invention relates generally to components and attachments for wheelchairs. The present invention relates more specifically to mechanisms for rotational and removable attachment of a leg rest to a wheelchair.
2. Description of the Related Art
Early examples of efforts to attach leg and foot rests to wheelchairs in a manner that permits their rotation to the side include the following patents:
U.S. Pat. No. 4,176,879 issued to Rodaway on Dec. 4, 1979 entitled Wheelchair Foot Rest Latch describes a foot rest hinge structure that includes two support pin hinge points and a third retractable pin latch point. The type of hinge system described places considerable wear on two relatively weak pivot points and further requires significant manipulation by the user to release.
U.S. Pat. No. 4,770,467 issued to Zinn on Sep. 13, 1988 entitled Foot Rest Unit for Wheelchairs describes a tubular hinge arrangement that provides a much stronger pivot point but requires, as a result, a much more complicated release mechanism. In this case the release mechanism comprises four buttons (on each leg rest) that must be depressed against a spring in order to release and rotate the leg rest.
FIGS. 1a and 1b attached hereto shows a more recent effort to provide stability and strength to a releasable/rotating leg rest. FIG. 1a is a side view showing in schematic form the basic structure of this common leg rest system used in the prior art. FIG. 1b is a top view of the same components of the leg rest system shown in FIG. 1a. In FIG. 1a, foot rest 10 is comprised of foot plate 16 connected by leg tube 12 to hanger bracket 14. Hanger bracket 14 is a cap structure that receives and retains leg tube 12 as well as hinge post 18. Foot rest 10 is received by frame sleeve 24 which is rigidly fixed on the frame of the wheelchair (not shown). Frame sleeve 24 positions sleeve tube 22 with cylindrical opening 28 so as to receive hinge post 18 therein. Hinge post 18 and opening 28 are sized for a snug but rotatable fit.
To direct foot rest 10 towards the front to its most common position suitable for receiving the foot of the user, hinge post 18 in the prior art is fixed with a pair of opposing pins 20 that engage depressions 26 formed in sleeve tube 22. In this manner foot rest 10 may be moved to the side by forcing the rotation of hinge post 18 within sleeve tube 22 such that pins 20 are forced up and out of depressions 26. Release of the foot rest and rotation back towards the front allows pins 20 to once again fall into depressions 26 and to be held loosely captive therein.
Two primary problems arise with each of the above designs in the prior art. The first problem results from a hinge mechanism that is weak and therefore susceptible to breakage and/or excessive wear. The second problem results from a hinge mechanism that is difficult for the user of the wheelchair to manipulate. Unfortunately it has been difficult to address both of these problems at the same time as rugged hinge mechanisms tend to be difficult to manipulate and easily manipulated hinges tend to break or wear excessively.
It would be desirable to have a leg rest hinge assembly that is both rugged and resistant to breakage and wear, and at the same time is easily manipulated by the user. It would be desirable if such a leg rest hinge structure had a wide range of rotation when released but a firm fixed retention when engaged. It would further be desirable if such a leg rest structure could be adapted for retrofit to existing wheelchairs with minimal modifications to the wheelchair frame.
It is therefore an object of the present invention to provide a leg rest for a wheelchair that may be alternately fixed in a forward position or a side rotated position.
It is an object of the present invention to provide a rotating leg rest for a wheelchair having a hinge mechanism that is of rugged construction such that it resists breakage and wear during repeated use.
It is a further object of the present invention to provide a rotating leg rest for a wheelchair having a releasable latch mechanism tending to position the leg rest in a forward position for use but releasable to permit rotation to the side during non-use.
It is a further object of the present invention to provide a rotating leg rest for a wheelchair having a releasable latch mechanism that itself is rugged and resistant to breakage and yet is easily manipulated by the wheelchair user.
In fulfillment of these and other objectives the present invention provides an improved leg rest hinge structure for a wheelchair that is both strong and easily manipulated. The hinge structure includes a hinge post inversely mounted to a hinge cap which retains the leg tube and foot plate of the leg rest. The hinge post is removably and rotationally inserted into a cylindrical socket fixed to the frame of the wheelchair. A flat land is formed on the exterior circumference of the cylindrical socket that engages either a matching land formed on the underside of the hinge cap or a spring loaded pivot plate fixed on the hinge cap adjacent the hinge post. The structure provides a rugged single post hinge point and an easily manipulated mechanism for releasing the leg rest for rotating it to the side and out of the way.